-] 



PALAEOZOIC OSTRACODA. 65 



vinco of Quebec, there are many small ostracoda, and among these are 

 many varieties of Primitia mundula. Some ai-e i-ehitively longer and 

 narrower than the type and approaching P. Logani^ with the sulcus 

 either mid-dorsal or nearer to one end. 



Another variety, here figuicd (pi. x, fig. 9), is peculiar in having 

 an obliquely triangular sulcus, with high sides, which make the valve 

 wQYy convex. 



Although at first T thought these several forms might be of specific 

 value ((^uart. Jour. Geol. Soc, vol. XLVJ, p. 553), it does not so ap- 

 pear to me now, and they will stand as noticeable varieties. This 

 figured specimen may be called var. incisa. (Jollected by Mr. II. M. 

 Ami, in 1888. 



G. Beyriciiia clavigera (sp. nov.). 

 PI. 11, fig. V. 

 Beyrichia, sp. nov. Quart. Jour. Geol. Soc, vol. XLVII, 1890, p. 553. 

 Length 4*1 (hinge line 2*0), height 2*5 mm. 



Subovate, with a straight, short hinge-line; broad-lobed ; the two 

 main lobes are of nearly equal bulk, but the hinder one is the larger of 

 the two ; they unite with a broad curved junction below ; the middle 

 lobe is isolated, of an in-egular club-shape (reversed) ; a low, subsidiary 

 ridge is Just within the margin of the obliquely curved, projecting, 

 posterior margin. Individuals vary in their proportions, besides being 

 modified by pressure. Abundant in dark coloured, micaceous, shaly 

 mudstone, somewhat ferruginous. Chazy Shales, Broad street, Aylmer, 

 (Quebec. (Collected by Mr. T. W. K. Sowter. 



Y. Beyriciiia clavigera (sp. nov.) Var. clavipracta (nov.), 



PI. 11, fig. 8. 



Length 3 4 (hinge-line 2*0), height 2-3 mm. 



In this form the middle lobe is divided into two small lobes or 

 tubercles, corresponding to the moieties above and below the constric- 

 tion of the mid-lobe in fig. 7 ; and the upper part of the anterior lobe has 

 develo])ed a small tubercle; all the surface is punctate, and the pos- 

 terior margin is not so oblique and projecting as in the type. 



Accomi)anying the foregoing in the Chazy Shales of Aylmer, Quebec. 

 Collected by Mr. T. W. 1^]. Sowter. 



